Loading of libraries in an `expl3` context

[dbitouze]

Brief outline of the proposed feature

When expl3-syntax is activated you can nevertheless load other packages without problems. This here does "the right thing":

\ExplSyntaxOn
....
\usepackage{tikz}
....
\ExplSyntaxOff

But the same is not true when loading package “libraries”. You can't use e.g. \usetikzlibrary{calc} without getting errors.

There are workarounds discussed here.

Usage example

The compilation of the following MCE fails:

\begin{filecontents*}[overwrite]{myclass.cls}
\ProvidesExplClass
  {myclass}
  {2022/11/01}
  {0.1}
  {
    My Nice Class
  }
\NeedsTeXFormat{LaTeX2e}
\LoadClass { article }
%
\RequirePackage{tikz}
\usetikzlibrary{calc}
\end{filecontents*}

\documentclass{myclass}
\begin{document}
Foo.
\end{document}

with the following error:

! Package pgfkeys Error: I do not know the key '/tikz/cs/point/.storein', to which you passed '\tikz@cs@point ', and I am going to ignore it. Perhaps you misspelled it.

due to the category regime induced by the implicit \ExplSyntaxOn introduced by \ProvidesExplClass, which drops the keyboard spaces.

[hmenke]

Please test the following patch. Please also keep in mind that you can only sensibly use TikZ with the traditional (initex) catcodes.

diff --git a/tex/generic/pgf/utilities/pgfkeys.code.tex b/tex/generic/pgf/utilities/pgfkeys.code.tex
index f24557f8..989f47d0 100644
--- a/tex/generic/pgf/utilities/pgfkeys.code.tex
+++ b/tex/generic/pgf/utilities/pgfkeys.code.tex
@@ -1213,7 +1213,10 @@
       \catcode`\|=12
       \catcode`\$=3
       \pgfkeys@IfFileExists{pgfkeyslibrary\[email protected]}{%
+        \csname @pushfilename\expandafter\endcsname
+        \expandafter\xdef\csname @currname\endcsname{pgfkeyslibrary\[email protected]}%
         \input pgfkeyslibrary\[email protected]
+        \csname @popfilename\endcsname
       }{%
         \pgfkeys@error{I did not find the pgfkeys library '\pgf@temp'. I looked for the
           file named pgfkeyslibrary\[email protected], but could not find it in the
diff --git a/tex/generic/pgf/utilities/pgfutil-common.tex b/tex/generic/pgf/utilities/pgfutil-common.tex
index 0ecdc688..275f4189 100644
--- a/tex/generic/pgf/utilities/pgfutil-common.tex
+++ b/tex/generic/pgf/utilities/pgfutil-common.tex
@@ -244,7 +244,13 @@
   \fi
   \closein\pgfutil@inputcheck}
 
-\def\pgfutil@InputIfFileExists#1#2#3{\pgfutil@IfFileExists{#1}{\input #1\relax#2}{#3}}%
+\def\pgfutil@InputIfFileExists#1#2#3{%
+  \pgfutil@IfFileExists{#1}{%
+    \csname @pushfilename\expandafter\endcsname
+    \expandafter\xdef\csname @currname\endcsname{#1}%
+    \input #1\relax
+    \csname @popfilename\endcsname
+    #2}{#3}}%
 
 
 % pgfutil@loop (from plain.tex)

[dbitouze]

Please test the following patch.

Quite weird: with an up to date TeX Live 2022, the pgfkeys.code.tex file contains only 1160 lines:

$ wc -l  /home/bitouze/texlive/2022/texmf-dist/tex/generic/pgf/utilities/pgfkeys.code.tex 
1160 /home/bitouze/texlive/2022/texmf-dist/tex/generic/pgf/utilities/pgfkeys.code.tex

so doesn't contain any \pgfkeys@IfFileExists{pgfkeyslibrary\[email protected]}{% line.

Just to be sure:

$ wget -q http://mirrors.ctan.org/graphics/pgf/base/tex/pgfkeys.code.tex && wc -l pgfkeys.code.tex
1160 pgfkeys.code.tex

[muzimuzhi]

I think Henri's patch is based on the latest pgfkeys.code.tex, which contains some not-yet-released changes. Nevertheless the key is to patch \pgfkeys@IfFileExists in pgfkeys.code.tex and \pgfutil@InputIfFileExists in pgfutil-common.tex.

[dbitouze]

I think Henri's patch is based on the latest pgfkeys.code.tex, which contains some not-yet-released changes.

@muzimuzhi That's what I wanted to stress out :smile:

Nevertheless the key is to patch \pgfkeys@IfFileExists in pgfkeys.code.tex and \pgfutil@InputIfFileExists in pgfutil-common.tex.

The point is, at least \pgfkeys@IfFileExists doesn't exist in current pgfkeys.code.tex.

[muzimuzhi]

Nevertheless the key is to patch \pgfkeys@IfFileExists in pgfkeys.code.tex and \pgfutil@InputIfFileExists in pgfutil-common.tex.

The point is, at least \pgfkeys@IfFileExists doesn't exist in current pgfkeys.code.tex.

Sorry, my bad. \pgfkeys@IfFileExists is added for the unreleased feature---pgfkeys library, so you can omit the patch to it for now.